Studies of Magnetic Flux and Critical Current Distributions Near the Surface in Type II Superconductors.
OHIO UNIV ATHENS DEPT OF PHYSICS
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Very pure annealed Nb samples were irradiated with 3.2 and 5 McV protons to fluences of about 6.8 x 1016 pcm2. Local magnetic induction profiles, when the samples were in the superconducting mixed state, were obtained using an ac technique. Electron micrographs of the same irradiated samples show dislocation loops in the damaged region of the samples. The critical current and the volume flux pinning force were determined from the slope of the measured field profiles. Assuming pinning due to the observed dislocation loops, the pinning force calculated from a direct summation law is an order of magnitude higher than the experimental result and as calculated from quadratic summation laws is two to three orders of magnitude smaller than measured. Author
- Electricity and Magnetism